1. Field of the Invention
The present invention relates generally to a machine tool with an automatic tool change apparatus, and more particularly to a machine tool installing a tool storage magazine, extending within a column which slidably supports a spindle head.
2. Description of the Prior Art
In general, in a machine tool with an automatic tool change apparatus wherein a spindle head is mounted on a side surface of a column for a vertical sliding movement, a tool storage magazine is provided on the spindle head or on the top or the side of the column.
In a machine tool providing a tool storage magazine on a spindle head, a tool change operation can be performed at any position of the spindle head. However, the number of tools to be stored is considerably limited and the weight of the spindle head becomes large because of the tool storage magazine.
In a machine tool providing a tool storage magazine on the top or the side of a column, the tool storage magazine is installed remote from the spindle head. For this reason, where the tool storage magazine is provided on the top of the column, the spindle head has to be moved to an upper position at every tool change operation, which results in a longer time loss and a poor manipulation of the tool storage magazine. Where the tool storage magazine is provided on the side of the column, the distance between the tool storage magazine and the spindle head becomes large and therefore an additional tool transfer device has to be provided to transfer a tool from the tool storage magazine to a tool change position where a tool change arm performs a tool change operation, which results in complicated construction and a longer tool change operation.